Manufacture of steel



UNITED STATES PATENT OFFICE.

ALADAR PACZ, OF CLEVELAND, OHIO, ASSIGNOR TO GENERAL ELECTRIC. COMPANY,A CORPORATION OF NEW YORK.

MANUFACTURE or STEEL.

No Drawing.

To all whom it may concern:

Be it known that I, ALADAR PACZ, a citizen of the United States,residing at Cleveland, in the county of Cuyahoga and State of Ohio, haveinvented a new and useful Improvement in the Manufacture of Steel, ofwhich the following is a specification.

My invention relates to improvements in the manufacture of steel andwhile of gen eral application to steel manufacture it applies moreparticularly to the manufacture of so-called alloy steels, in whichthere is incorporated with the steel one or more metals, such astungsten, vanadium, chromium, molybdenum and uranium to produce steelssuitable for tools, vehicle parts and other articles requiring metalhaving especial hardness, toughness, tensile strength, etc. The objectof my invention is to pro duce steels having better physicalcharacteristics and also to render such steels more uniform and freefrom defects.

According to my invention, I incorporate with the steel a certainpercentage of tantalum or niobium or both and either of these or bothmay be incorporated in the steel alone or in combination with suchmetals as tungsten, vanadium, chromium. molybdenum o-r uranium orcombinations of these, depending upon the nature of the steel desired.The incorporation of the tantalum or niobium improves the steel in anycase and my invention, in its broadest aspect, comprehends theutilization of tantalum or niobium in the manufacture of steel ingeneral. It is to be understood, however, that my invention relates moreparticularly to the so-called alloy steels where the production of asuperior metal is the main object sought and where the cost in thesteel, provided the desired qualities are secured, is not of suchcontrolling importance as in the case of ordinary steel.

The toughening and hardening properties given to the steel by niobium ortantalum are increased as compared with those given by vanadium,tungsten, chromium, and molybdenum on account of the lower specificgravity of the niobium as compared for instance with molybdenum and thatof tantalum as compared with tungsten. A given weight of niobium, and oftantalum, therefore, having a greater volume will exert a greaterinfluence. The oxide of molybdenum and tungsten, especially theSpecification of Letters Patent.

Patented Apr. 5, 1921.

former, are more volatile than those of niobium and tantalum. Inconsequence of this, the elfect of niobium and tantalum is morepermanent when the metal is heated on ac-' count of less volatilizationof the oxids which are formed. Another advantage possessed by theniobium and tantalum is the greater afiinity for gases, such ashydrogen, than other metals used for hardening and toughening steel. Theniobium and tantalum also combine with any nitrogen or oxygen which maybe present, thus purifying the metal bath and rendering the resultantmetal more uniform.

In incorporating the tantalum or niobium or both, these metals singly ortogether may be added directly to the steel bath or a ferro alloycontaining either one or both may be added or, in case it is desired toproduce a metal containing tungsten, molybdenum, chromium or vanadium,the desired percentages of these metals may be incorporated in the ferroalloy. These ferro alloys may be produced either by reducing the metalsfrom the oxids of niobium or tantalum or both by means of carbon, asufiicient quantity of iron being added toform a desired alloy. Anothermethod is to reduce by means of carbon the niobium or tantalum directlyfrom the ores columbite or tantalite, in a manner similar to thatfollowed in the production of ferro tungsten. In high speed steel, asnow manufactured, the tungsten averages from 12 to 20%. According to myinvention if it. is desired to replace the tungsten entirely withniobium or tantalum, a less percentage of these singly or in combinationmay be used than the percentage of tungsten. For instance, in case ofniobium the percentage may average from 6 to 12, while in the case oftantalum the percentage may run from. 8 to 16. If a combination is usedthe proper modification of these amounts will be obvious. In case all ofthe tungsten is not eliminated and it is desired to retain a certainpercentage of the tungsten while having present either the niobium ortantalum in less quantities than when they are used without thetungsten, the proper percentages can be readily calculated or indeedthese percentages may be determined readily by experimentation. Forexample, about 3 to 6% niobium may be used with 6 to 10% of tungsten or4 to 8% tantalum may be used with 6 to 10% tungsten. When all threemetals are utilized the niobium may run from 2 to 4%, the tantalum from3 to 6%, and the tungsten from 4 to 8%.

Niobium and tantalum or both may be introduced into the steel byintroducing theconcentrates and a suitable reducing agent just as isdone in the production of tungsten steel. Another method is to introducethem in the form of a, ferro alloy produced either from the oxids or theore, just as is in the production of ferro tungsten. Still anothermethod which maybe used when it is desired to incorporate the othermetals, such ashere- I inbefore referred to, is to combine the concentrates of niobium or tantalum with the concentrates of these othermetals and then to throw the whole mixture into the steel bath. In themanufacture of ferro-tungsten and ferro-chrome and other ferro alloys ofthisnature, the niobium or tantalum concentrate may be mixed with theconcentrate of tungsten, molybdenum, chromium, etc., and incorporatedwith the ironto produce a ferro-tungsten, ferro-ch'rome,ferro-molybdenum, containing a certain percentage of niobium ortantalum; These products can be distributed assubstitutes for thepresent ferro alloys which are added to the bath in the roduction ofthese steels.

It wlllbe recognized that these are merely illustrations and that myinvention, ashereinbefore stated, is not limited to any particularproportions of these metals, but comprises in its scope the useofniobium or tantalum or both in steel alone or combined with otheralloying metals. In the claims I have used the expression metal of theniobium class to cover either tantalum or niobium.

Havin fully described m invention, what I c aim and desire to obtam byLetters Patent is; v

1. A steel containinga smallproportion of niobium. 1

2. .A steel containing a small proportion of niobium and tantalum.

3. Asteelcontai'ning a small proportion of niobium and at least one"other of the rarer metals ordinarily used for alloy steels. 4. A steelcontaining a small proportion of a metal of the niobium class and atleast one otherfof the rarer metals ordinarily used in alloy steels.

'5. A steel containing a small proportion of a metal of the nioblum'class in combination with tungsten.

6. High speedsteel containing a small proportlon of a metal of theniobium class.

Iigh speed steel containing .a small I 7 proportlon of niobium.

8. High speed steel containing a small proportlon of niobium andtantalum. v

9. A high speed steel containing a small proportion of a metal of theniobium class and at least one other of the rarer metals ordinarily usedin high speed steel.

10. High speed steel containing a small proportion of a metal of theniobium class in combination with tungsten. x

11. High speed steel containing a -small tungsten.

12. High speed steel containing av small proportion of niobium andtantalum in combination with tungsten.

13. A. steel containing niobium in the proportion of-three to twelve perCent.

14;. A steel containing niobium and tantalum the proportion of three tosix per cent. niobium, and four to eight per cent. tantalum.

15. A steel containing tungsten, niobium or tantalum, the niobium beingin the proportion ofvthree to six per cent, and the tungsten in theproportionof six to ten per cent...

16. A steel containing tungsten, niobium and tantalum, the tungstenbelngin the proportion offour to eight per cent, the niobium'two to fourper cent, and the tantalum three to six per cent; 4

' v ALADAR PACZ.

' proportion of niobium in combination with

